Re: Is it possible to prove a negative?
« Reply #60 on: December 30, 2013, 03:31:11 AM »
An expression of skepticism is a negative claim, not a positive claim. The burden of proof is on those with the positive claims.

"There is no evidence of ghosts" is an expression of skepticism, and is a negative claim. The burden of proof, consequentially, is on the people claiming the existence of ghosts.

Claiming that 'it does not exist' is a negative claim, and does not need to be proven. It is that which must be assumed before all else.

It is positive claims which carry the burden of proof.

I have a feeling that if I searched .org I could find many examples of you stating explicitly that one cannot prove a negative, but maybe not.

I'm disputing that negative/positive is a meaningful distinction for an assertion, and I'm disputing that an assertion is relieved of its burden of proof simply because it contains a negation.  All assertions have a burden of proof.  Assertions are not negative or positive.  That's not a real thing.

I'm most strongly disputing that one should assume any claim containing a negation to be true until proven otherwise.  Every claim with a negation can be reformulated into a claim without one. 'Not P is true' is the same as 'P is false.'  It makes no sense to suggest that we should believe any and all assertions that contain negations until the contrary assertion has been proven.

This iteration of the forums are new, but there were lots of posts from different users on .org that commonly made the claim that 'negative claims cannot be proven.'  The gravity thread made me think of those, so I posted this thread. 
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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #61 on: December 30, 2013, 03:57:18 AM »
I'm disputing that negative/positive is a meaningful distinction for an assertion, and I'm disputing that an assertion is relieved of its burden of proof simply because it contains a negation.  All assertions have a burden of proof.  Assertions are not negative or positive.  That's not a real thing.

I'm most strongly disputing that one should assume any claim containing a negation to be true until proven otherwise.  Every claim with a negation can be reformulated into a claim without one. 'Not P is true' is the same as 'P is false.'  It makes no sense to suggest that we should believe any and all assertions that contain negations until the contrary assertion has been proven.

This iteration of the forums are new, but there were lots of posts from different users on .org that commonly made the claim that 'negative claims cannot be proven.'  The gravity thread made me think of those, so I posted this thread.

The burden of proof is clearly on the person with the positive claim. In an argument on the existence of ghosts, if someone claims that ghosts exist, is it the burden of that person to provide evidence for the existence of ghosts? Or, is it the burden of the person claiming that ghosts do not exist to provide evidence of their non-existence?

Clearly, the burden is on the person claiming that ghosts exist to prove that claim. There is already plenty of evidence that ghosts DON'T exist. The burden of the skeptic to provide evidence that ghosts don't exist has been automatically met, by virtue of a life long experience that ghosts do not exist.

This is why the burden is always on the person with the positive claim. The negative claim is trivial to prove.
« Last Edit: December 30, 2013, 04:03:20 AM by Tom Bishop »

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Offline Rama Set

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Re: Is it possible to prove a negative?
« Reply #62 on: December 30, 2013, 04:06:48 AM »
I'm disputing that negative/positive is a meaningful distinction for an assertion, and I'm disputing that an assertion is relieved of its burden of proof simply because it contains a negation.  All assertions have a burden of proof.  Assertions are not negative or positive.  That's not a real thing.

I'm most strongly disputing that one should assume any claim containing a negation to be true until proven otherwise.  Every claim with a negation can be reformulated into a claim without one. 'Not P is true' is the same as 'P is false.'  It makes no sense to suggest that we should believe any and all assertions that contain negations until the contrary assertion has been proven.

This iteration of the forums are new, but there were lots of posts from different users on .org that commonly made the claim that 'negative claims cannot be proven.'  The gravity thread made me think of those, so I posted this thread.

The burden of proof is clearly on the person with the positive claim. In an argument on the existence of ghosts, if someone claims that ghosts exist, is it the burden of that person to provide evidence for the existence of ghosts? Or, is it the burden of the person claiming that ghosts do not exist to provide evidence of their non-existence?

Clearly, the burden is on the person claiming that ghosts exist to prove that claim. There is already plenty of evidence that ghosts DON'T exist. The burden of the skeptic to provide evidence that ghosts don't exist has been automatically met, by virtue of a life long experience that ghosts do not exist.

This is why the burden is always on the person with the positive claim. The negative claim is trivial to prove.

Incorrect:

http://en.wikipedia.org/wiki/Philosophic_burden_of_proof#Proving_a_negative

It may be trivial to fulfill your burden in some cases, but that does not free one from the burden.  Anytime a truth is asserted it carries a burden of proof.  It is very simple.

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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #63 on: December 30, 2013, 04:20:05 AM »
I'm disputing that negative/positive is a meaningful distinction for an assertion, and I'm disputing that an assertion is relieved of its burden of proof simply because it contains a negation.  All assertions have a burden of proof.  Assertions are not negative or positive.  That's not a real thing.

I'm most strongly disputing that one should assume any claim containing a negation to be true until proven otherwise.  Every claim with a negation can be reformulated into a claim without one. 'Not P is true' is the same as 'P is false.'  It makes no sense to suggest that we should believe any and all assertions that contain negations until the contrary assertion has been proven.

This iteration of the forums are new, but there were lots of posts from different users on .org that commonly made the claim that 'negative claims cannot be proven.'  The gravity thread made me think of those, so I posted this thread.

The burden of proof is clearly on the person with the positive claim. In an argument on the existence of ghosts, if someone claims that ghosts exist, is it the burden of that person to provide evidence for the existence of ghosts? Or, is it the burden of the person claiming that ghosts do not exist to provide evidence of their non-existence?

Clearly, the burden is on the person claiming that ghosts exist to prove that claim. There is already plenty of evidence that ghosts DON'T exist. The burden of the skeptic to provide evidence that ghosts don't exist has been automatically met, by virtue of a life long experience that ghosts do not exist.

This is why the burden is always on the person with the positive claim. The negative claim is trivial to prove.

Incorrect:

http://en.wikipedia.org/wiki/Philosophic_burden_of_proof#Proving_a_negative

It may be trivial to fulfill your burden in some cases, but that does not free one from the burden.  Anytime a truth is asserted it carries a burden of proof.  It is very simple.

A negative claim is such that it is already automatically proven. I don't need to prove that ghosts don't exist because their non-existence is already established by experience.

The burden is on the person claiming that ghosts exist. My responsibility for proving that ghosts do not exist extends to me opening my eyes and seeing that they do not exist.
« Last Edit: December 30, 2013, 04:21:55 AM by Tom Bishop »

Offline bj1234

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Re: Is it possible to prove a negative?
« Reply #64 on: December 30, 2013, 04:27:38 AM »
I'm disputing that negative/positive is a meaningful distinction for an assertion, and I'm disputing that an assertion is relieved of its burden of proof simply because it contains a negation.  All assertions have a burden of proof.  Assertions are not negative or positive.  That's not a real thing.

I'm most strongly disputing that one should assume any claim containing a negation to be true until proven otherwise.  Every claim with a negation can be reformulated into a claim without one. 'Not P is true' is the same as 'P is false.'  It makes no sense to suggest that we should believe any and all assertions that contain negations until the contrary assertion has been proven.

This iteration of the forums are new, but there were lots of posts from different users on .org that commonly made the claim that 'negative claims cannot be proven.'  The gravity thread made me think of those, so I posted this thread.

The burden of proof is clearly on the person with the positive claim. In an argument on the existence of ghosts, if someone claims that ghosts exist, is it the burden of that person to provide evidence for the existence of ghosts? Or, is it the burden of the person claiming that ghosts do not exist to provide evidence of their non-existence?

Clearly, the burden is on the person claiming that ghosts exist to prove that claim. There is already plenty of evidence that ghosts DON'T exist. The burden of the skeptic to provide evidence that ghosts don't exist has been automatically met, by virtue of a life long experience that ghosts do not exist.

This is why the burden is always on the person with the positive claim. The negative claim is trivial to prove.

Incorrect:

http://en.wikipedia.org/wiki/Philosophic_burden_of_proof#Proving_a_negative

It may be trivial to fulfill your burden in some cases, but that does not free one from the burden.  Anytime a truth is asserted it carries a burden of proof.  It is very simple.

A negative claim is such that it is already automatically proven. I don't need to prove that ghosts don't exist because their non-existence is already established by experience.

No negative claims are not automatically proven.  It has been shown to you multiple times that negative claims also carry a burden of proof.  Why do you assume that negative claims are automatically true?

Use Pizza's example

I claim
"There is no handkerchief in Pizza's pocket"

It cannot be assumed to be a true statement until all the logical places are checked.  Have I checked in his pocket? No.  Therefore, it cannot be claimed that it is automatically a true statement.

I might be able to create a logical argument and deduce that my statement is correct, however, my claim is not automatically true.

In reality, the only position I can take, without any further evidence, is that

"I do not know if Pizza has a handkerchief in his pocket"

Until I check Pizza's pockets, or someone else does, I cannot know for certain what is in Pizza's pocket.

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Offline markjo

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Re: Is it possible to prove a negative?
« Reply #65 on: December 30, 2013, 04:31:11 AM »
Why was this thread made?

To determine the validity of assertions like this one:
A negative claim is such that it is already automatically proven.
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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #66 on: December 30, 2013, 06:09:26 AM »
No negative claims are not automatically proven.  It has been shown to you multiple times that negative claims also carry a burden of proof.  Why do you assume that negative claims are automatically true?

The negative claims automatically meets the burden of proof by virtue of being a negative.

Quote
Use Pizza's example

I claim
"There is no handkerchief in Pizza's pocket"

The base truth is that there is no handkerchief in Pizza's pocket. My experience says that there is no handkerchief. Your experience says that there is no handkerchief. No one has seen any such handkerchief. All available evidence says there is none, therefore there is no handkerchief until demonstrated otherwise. If anyone is claiming existence of a handkerchief, the burden is on them.

Quote
In reality, the only position I can take, without any further evidence, is that

"I do not know if Pizza has a handkerchief in his pocket"

Until I check Pizza's pockets, or someone else does, I cannot know for certain what is in Pizza's pocket.

When we speak, we speak from our own knowledge. If you make a statement that "diamonds are the hardest rock" it is because you believe that diamonds are the hardest rock. There is no difference if you preface the statement with "As far as I know, diamonds are the hardest rock". Each statement is equally of your own belief.

If I state that there is no handkerchief in Pizza's pocket I am speaking truthfully from my own knowledge, and therefore that can be said. It is impossible to speak from someone else's knowledge or from a universal truth. It is the present knowledge in the discussion.
« Last Edit: December 30, 2013, 06:30:08 AM by Tom Bishop »

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Offline Rama Set

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Re: Is it possible to prove a negative?
« Reply #67 on: December 30, 2013, 06:15:23 AM »
Quote
Use Pizza's example

I claim
"There is no handkerchief in Pizza's pocket"

The base truth is that there is no handkerchief in Pizza's pocket.

The base truth is that you do not know for certain.
Quote
My experience says that there is no handkerchief. Your experience says that there is no handkerchief. No one has seen any such handkercheif. There is no handkerchief until demonstrated otherwise.

Incorrect.  Your ignorance does not satisfy a burden of proof.

 
Quote
If anyone is claiming existence of a handkerchief, the burden is on them.

What if no one has claimed the existence of a handkerchief, but you are merely asserting it?

[/quote]
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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #68 on: December 30, 2013, 06:46:37 AM »
The base truth is that you do not know for certain.

The available evidence says that there is no handkerchief, therefore that is what is concluded. The conclusion stays that way until positive evidence is presented of this handkerchief.

Quote from: Rama Set
Quote
My experience says that there is no handkerchief. Your experience says that there is no handkerchief. No one has seen any such handkercheif. There is no handkerchief until demonstrated otherwise.

Incorrect.  Your ignorance does not satisfy a burden of proof.

Absence of evidence is evidence of absence. The websites saying otherwise are authored by people trying to justify their belief in ghosts, aliens, and magical fairies who live in the sky.

See: http://oyhus.no/AbsenceOfEvidence.html

Quote
an anecdote from Roar Lauritzsen about Absence of Evidence:

"Suppose you are a programmer, and you are looking for bugs in a program. At first you cannot sleep at night because you are convinced that there must be a bug somewhere, you just haven't found it yet. To find the bug, you test the program to see if you find something that doesn't work as you expected. If you found something, it would be evidence that there was a bug. If you test the program a lot, and still find no evidence of a bug, this increases your confidence that there is no bug. In other words, it counts as evidence for the absence of a bug, and you are finally able to sleep better.

After a while, your program is thoroughly tested, and you still find no evidence for a bug. You begin to suspect that there might not be a bug after all. However, if there is no bug, you will have no purpose as a programmer. You feel as if your life depends on the existence of a bug. You are now looking for the Bug that will save you. You believe that there must be a Bug, so you test your program even more thoroughly. When you still cannot find any evidence for a Bug, you start to rationalize: Although I cannot find any Bug, that does not prove that there is no Bug. You are now a true believer in the Bug."


Quote from: Rama Set
Quote
If anyone is claiming existence of a handkerchief, the burden is on them.

What if no one has claimed the existence of a handkerchief, but you are merely asserting it?

If no one has claimed the existence of a handkerchief and I had merely asserted that there is no handkerchief, then it is still not my burden to demonstrate that there is no handkerchief beyond the evidence which already tells us that there is none. The burden was already met with evidence. It is this evidence which must be contradicted.
« Last Edit: December 30, 2013, 06:54:30 AM by Tom Bishop »

Offline bj1234

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Re: Is it possible to prove a negative?
« Reply #69 on: December 30, 2013, 12:20:34 PM »
Well see in your example of the bug in a program, the programmer is looking for a bug where it is most likely to be.  In the program.  Not some other program or in your drawers.  He is looking in the program.  If he can't find a bug where a bug is supposed to be, that is supporting his claim.  However, he sure wouldn't have a long career as a programmer if he developed his code, submitteded it and claimed the are no bugs in this program.  I don't need to test it.  It isn't my responsibility to do so. 

Just as if I claimed there is no handkerchief is Pizza's pocket, it is my burden to actually check Pizza's pocket for a lack of handkerchief.

Offline bj1234

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Re: Is it possible to prove a negative?
« Reply #70 on: December 30, 2013, 12:36:33 PM »
Oh and yes there is a huge difference between making a claim and stating a belief.

Stating

There is no X.

Is not the same as saying

As far as I know, there is no X.

The first you are asserting that you know, for a fact, and that you have examined all sorts of research or data.
The second, you are acknowledging that you have a limited grasp on the subject, but from what you have seen, X does not exist.

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Offline Rama Set

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Re: Is it possible to prove a negative?
« Reply #71 on: December 30, 2013, 01:12:18 PM »
Tom-Absence of evidence is evidence of absence if you exhaust the domain of the claim. If the absence is due to ignorance, it is not sufficient to fulfill a burden. For example, not finding specs of an ESA satellite experiment in your briefcase would not be sufficient to prove an absence of evidence. You have not looked anywhere near where evidence would be should you assume its existence.
« Last Edit: December 30, 2013, 01:16:45 PM by Rama Set »
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Offline markjo

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Re: Is it possible to prove a negative?
« Reply #72 on: December 30, 2013, 02:25:18 PM »
The base truth is that you do not know for certain.

The available evidence says that there is no handkerchief, therefore that is what is concluded. The conclusion stays that way until positive evidence is presented of this handkerchief.
Tom, please define "available evidence".  For example, do you want your doctor to declare that you do not have cancer before or after he examines you?  After all, if he doesn't examine you, then he can't find any evidence of cancer. 
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If you can't demonstrate it, then you shouldn't believe it.

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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #73 on: December 30, 2013, 04:52:05 PM »
Well see in your example of the bug in a program, the programmer is looking for a bug where it is most likely to be.  In the program.  Not some other program or in your drawers.  He is looking in the program.  If he can't find a bug where a bug is supposed to be, that is supporting his claim.  However, he sure wouldn't have a long career as a programmer if he developed his code, submitteded it and claimed the are no bugs in this program.  I don't need to test it.  It isn't my responsibility to do so. 

Just as if I claimed there is no handkerchief is Pizza's pocket, it is my burden to actually check Pizza's pocket for a lack of handkerchief.

No, it is not your burden to check, or the programmer's for that matter. The burden is on the party with the positive claim.

If someone claims that a bug in the software exists, that person would be burdened to demonstrate or provide information on that bug. The programmer wouldn't be burdened with searching through a needle in a haystack of code for some sort of bug. There is already evidence that a bug does not exist. The claimant must demonstrate the assertion.

In a discussion of ghosts it is not my burden to 'prove that ghosts don't exist'. It is the burden of the claimant to demonstrate the existence of ghosts. There is already evidence that ghosts do not exist.

In a discussion of the handkerchief, the current evidence in the discussion is that there is no such handkerchief.

In a discussion of whether schematics exist of a gravity measuring space ship built to withstand magnetic interference, the evidence is that there is no such schematic.

Positive evidence is required for all of that. Our current knowledge and experience tells us that none of that exists. The most likely place to check for those things is with the party with that claim. If that party cannot provide the necessary evidence, then the proof falls flat.
« Last Edit: December 30, 2013, 05:14:29 PM by Tom Bishop »

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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #74 on: December 30, 2013, 04:56:32 PM »
Oh and yes there is a huge difference between making a claim and stating a belief.

Stating

There is no X.

Is not the same as saying

As far as I know, there is no X.

The first you are asserting that you know, for a fact, and that you have examined all sorts of research or data.
The second, you are acknowledging that you have a limited grasp on the subject, but from what you have seen, X does not exist.

Those statements are the same. You cannot speak from an ultimate truth in one sentence and then from your own belief in the next. They are both your belief.

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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #75 on: December 30, 2013, 04:59:16 PM »
Tom-Absence of evidence is evidence of absence if you exhaust the domain of the claim. If the absence is due to ignorance, it is not sufficient to fulfill a burden. For example, not finding specs of an ESA satellite experiment in your briefcase would not be sufficient to prove an absence of evidence. You have not looked anywhere near where evidence would be should you assume its existence.

I am looking right here on this forum where it is claimed that schematics exist of a certain type of magnetically-resistant satellite. This is the only place I have seen where is is suggested that such a thing exists, therefore this is the most likely place to look. The party claiming that it exists must post it here for all to see.

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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #76 on: December 30, 2013, 05:03:34 PM »
The base truth is that you do not know for certain.

The available evidence says that there is no handkerchief, therefore that is what is concluded. The conclusion stays that way until positive evidence is presented of this handkerchief.
Tom, please define "available evidence".  For example, do you want your doctor to declare that you do not have cancer before or after he examines you?  After all, if he doesn't examine you, then he can't find any evidence of cancer.

Your doctor does assume that you don't have cancer before he examines you. The moment you come in you are considered at a healthy state, which is why you are not carted to the emergency room before observational and diagnostic evidence is collected.

Only until evidence is presented, can the doctor say that you have an ailment. Otherwise, as far as he is concerned, you do not.
« Last Edit: December 30, 2013, 05:08:32 PM by Tom Bishop »

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Re: Is it possible to prove a negative?
« Reply #77 on: December 30, 2013, 05:11:32 PM »
The base truth is that you do not know for certain.

The available evidence says that there is no handkerchief, therefore that is what is concluded. The conclusion stays that way until positive evidence is presented of this handkerchief.
Tom, please define "available evidence".  For example, do you want your doctor to declare that you do not have cancer before or after he examines you?  After all, if he doesn't examine you, then he can't find any evidence of cancer.

Your doctor does assume that you don't have cancer before he examines you. The moment you come in you are considered at a healthy state, which is why you are not carted to the emergency room before observational and diagnostic evidence is collected.

Only until evidence is presented, can the doctor say that you have an ailment. Otherwise you do not.
Last I checked, a doctor doesn't assume anything until he checks you out, gets some diagnostic tests done, then compares the results to get a diagnosis of your health.  If the doctor assumed that you did not have cancer, he would not perform any sort of tests.

Just as if the programmer assumed there were no bugs in his program, he would not test it out to verify its operation.  He would just submit it and say, "there are no bugs"  There is a reason why people test things that they design or build.  It is to prove that there are no errors in it.


 

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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #78 on: December 30, 2013, 05:16:46 PM »
Last I checked, a doctor doesn't assume anything until he checks you out, gets some diagnostic tests done, then compares the results to get a diagnosis of your health.  If the doctor assumed that you did not have cancer, he would not perform any sort of tests.

He's doing it for the money.

If you would like to pay me a physician's wages to do tests and collect evidence, I would be happy to. Otherwise it is not my burden to provide evidence for the positive claims which you or anyone else has made.
« Last Edit: December 30, 2013, 05:18:51 PM by Tom Bishop »

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Re: Is it possible to prove a negative?
« Reply #79 on: December 30, 2013, 05:24:40 PM »
Well see in your example of the bug in a program, the programmer is looking for a bug where it is most likely to be.  In the program.  Not some other program or in your drawers.  He is looking in the program.  If he can't find a bug where a bug is supposed to be, that is supporting his claim.  However, he sure wouldn't have a long career as a programmer if he developed his code, submitteded it and claimed the are no bugs in this program.  I don't need to test it.  It isn't my responsibility to do so. 

Just as if I claimed there is no handkerchief is Pizza's pocket, it is my burden to actually check Pizza's pocket for a lack of handkerchief.

No, it is not your burden to check, or the programmer's for that matter. The burden is on the party with the positive claim.

In a discussion of ghosts it is not my burden to 'prove that ghosts don't exist'. It is the burden of the claimant to demonstrate the existence of ghosts. There is already evidence that ghosts do not exist.

In a discussion of the handkerchief, the current evidence in the discussion is that there is no such handkerchief.

In a discussion of whether schematics exist of a gravity measuring space ship built to withstand magnetic interference, the evidence is that there is no such schematic.

Positive evidence is required for all of that. Our current knowledge and experience tells us that none of that exists. The most likely place to check for those things is with the party with that claim. If that party cannot provide the necessary evidence, then the proof falls flat.
This is where you are making your faulty leap of logic.  You argument of ignorance.  Which is assuming that since it has not been proven to be true, it must be false.  You completely forget the third option of, we just do not have enough evidence to support either proving or disproving the statement.

Our current knowledge of if the lack of handkerchief in Pizza's pocket indicates that we cannot be sure.  Therefore we should not make any assumptions.  Now if I had made the initial claim of there not being a handkerchief in Pizza's pocket, It falls on me to support that claim. 

I could make some logical deductions, such as "I saw Pizza sneeze, he grabbed for a napkin from the table, if he had a handkerchief, he would have used that.  Therefore, I assume that he does not have a handkerchief in his pocket." 

However, I have never met Pizza, I have not seen him sneeze, therefore, I cannot make any assumptions about what he might have in his pockets.

The same goes for the schematics for the satellite.  I cannot claim that it has the required shielding.  Just as you cannot claim it doesn't. 

If you want to cast doubt on the claim that the satellite was adequate source for determining gravity variations, you can't make the claim that the satellite was not shielded.  You need to make the claim that "Since we do not know if the satellite was properly shielded, we cannot assume the accuracy of the experiment."

I really don't understand how you are not understanding this.